2. amps-preamps
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Biasing Cayin A 88T tube amp

I know this amp has been the target of much talk on this subject, but does anyone have a step by step guide to biasing this fantastic amp? I realize there are some dangerous voltages in there, and to do the job, you have to take the back plate off and switch the amp on right? But, where do I take the readings from, once I'm in there?

I'm sure there was a post on here with pictures, but I can't find it for love nor money.

Kindest regards

JP
peaman
afg
4 posts
 
JP, I have the instructions for the amp. It is a word doc. How do I send it to you?

You have to take the back plate off. There are resistors at from where you have to measure the voltage. The voltage has to be set at 0.4V on your multimeter by turning the pots. The amp has to be on for about 5-10 minutes before your measure. The speakers have to be connected but all sources have to be disconnected.

It is very simple but you have to be careful not to touch anything.
peaman OP
2 posts
 
Thanks ever so much for all your help!

Take care

JP
realdeal
63 posts
 
Biasing is making the plate current of the tube same as the other and that is done by adjusting the bias voltage or by adjusting the cathode bias resistor.
sonicbeauty
324 posts
 
I went through this years ago when I owned this same amp.

Take a bit of friendly advice. UNLESS you really know what your doing, I wouldn't open this up and start poking with a screwdriver in there.

It is a fantastic amp indeed, but the inability to bias this amp easily made it a non-keeper for sure in my book.
saki70
907 posts
 
Ditto Sonicbeauty's advice .
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